'Game of Thrones' just partially confirmed an epic theory fans have been waiting years to see

Warning: Spoilers ahead for "Game of Thrones,"
including speculation of future events.

"Game of Thrones" just set the stage for one of the most
anticipated showdowns in the series' history. We're talking, of
course, about Cleganebowl. It's the theory which says that Sandor
"The Hound" Clegane is going to return to King's Landing in order
to fight his brother, Gregor "The Mountain" Clegane, to the
death.

With the reveal of "The Hound" alive and well, "Game of
Thrones" has never been closer to finally making our Cleganebowl
dreams come true. Let's break this down piece by piece to weigh
the plausibility of this epic fight.

First, let's look at why this theory is relevant right now based
on events from recent season-six episodes.

Sandor Clegane lives

Season six, episode seven kicked off with a cold open showing
"The Hound" alive and living among a peaceful group of followers
of the Faith of the Seven. Their leader, a former soldier named
Ray, explains how he found "The Hound" very near death. "The
Hound" had been left for dead by Arya after he viciously fought
against Brienne of Tarth.

Fans had long hoped the "The Hound" was not truly dead, since we
never technically saw him die. This theory, known as the
"Gravedigger" theory, was the first crucial piece
of the Cleganebowl puzzle. Sunday's episode confirmed it with
"The Hound's" official return to the screen.

HBO

So "The Hound" lives. But what would make him fight against his
brother? Well, the folks who took him in were followers of the
Faith of the Seven. Though Ray seemed more interested in
spreading goodness around the world and less concerned with the
politics of King's Landing, this is the same faith that holds
power over the crown.

The High Sparrow has convinced Tommen to work with him, and the
High Sparrow will be the one overseeing Cersei Lannister's trial.

If the Faith requires a champion for a trial by combat, it's
possible that "The Hound" will offer his
services, especially when he learns who he'd be up against.

Which brings us to ...

A champion for the crown

The High Sparrow arrested Cersei in season
five for her role
in King Robert's death as well as her incestuous sexual habits
with her twin brother (Jaime) and cousin (Lancel). She did a
"walk of atonement" after admitting her affair with Lancel, but
she denied the other two charges. Those will be settled in a
pending trial by combat.

HBO

On the show so far, we have
never seen a trial concluded in a purely judicial manner. Tyrion
has twice stood accused of crimes, and both times he demanded a
trial by combat. A trial by combat allows the defendant to select
a "champion" to represent him in a fight to the death against the
selected champion of the prosecution. The guilt of the defendant
is determined by whether their champion wins or loses.

We know Cersei will demand a trial by combat, and
throughout season six she's made it clear that her champion with
be the zombified "Mountain."

Cleganebowl and the hype that won't die

These two separate incidences — zombie "Mountain" and "The
Hound's" predicted return — combined to give birth to the
Cleganebowl theory.

It started in 2013, when a 4chan thread about "Game of
Thrones" prompted a user to submit their theory:

The title for the theory was
likely inspired by the2013 NFL Super Bowl, when the coaches of the opposing teams also
happened to be brothers: Jim and John Harbaugh. Football fans and
sports announcers quickly nicknamed the game "The
Harbowl."

Since "The Hound" and "The Mountain" are brothers, and the
theory assumes that they will have an epic fight, Cleganebowl is
the best-fitting title. They share the same last name — Sandor
and Gregor Clegane — and this trial by combat would basically be
the equivalent of a Westerosi Super
Bowl.

This original 4chan thread references the "Valonqar"
prophecy, which we explained more here.
The gist of it is that Cersei went to a fortune teller when she
was younger and was told that she would be killed by the
"Valonqar." That is a term that means "younger brother." So the
Cleganebowl theory postulates that "The Hound" is the younger
brother in the scenario, and his victory will lead to Cersei's
execution.

Believers in the Cleganebowl are a unique brand of fans. The
tagline that generally follows any online allusions to the
involved characters is a simple: "GET HYPE." An entire
subreddit is dedicated to the converted believers, and this
Google search history shows the spikes of interest over the
years.

Cleganebowl subscribers have a flair for the unique. There
is a group of YouTube videos that mash up footage from the show
with glaring strobe-text and an intense
hip-hop/dubstep/electronic music soundtrack. Here are some of the
top-viewed ones — warning: NSFW language, loud music, and
lots of air horns:

Cleganebowl is such a popular theory not just because of its
outlandish fan base, but because it would actually be really
awesome to watch play out. "The Hound" and "The Mountain" are two
of Westeros' renowned fighters with a lot of anger to spare. They
have an intense rivalry — remember that it was "The Mountain" who
disfigured "The Hound's" face when they were children — that
would make a fight to the death extremely intense.

Air horns and Cleganebowl-hype
meters aside, there is sufficient evidence for the two main
components of the theory. "The Mountain" will represent Cersei in
her trial by combat on the show. "The Hound" has now returned,
and has a newfound loyalty to the Faith. At the end of Sunday's
episode, he grabbed an ax, potentially ready to go on a
killing spree and avenge his slaughtered clan.

Whether the brothers will actually fight to the death is
another story, but those who believe the hype will certainly wait
with bated breath to see if Cersei's trial plays out the way
we've been hoping all along.